Exploring the ecological roles of various animals in our world

“What’s the matter? Never seen a black-and-white before?”

I begin with a species that is treasured, criticized, even bemoaned and yet it is an icon of the conservation movement; coincidentally, this is the species I’m most frequently asked to explain its worthiness for continued existence. The species in question is the giant panda (Ailuropoda melanoleuca). These bears are recognized world-wide for their distinct black and white pattern, rounded faces with tufted ears and large eyes that immediately trigger our reaction to cuteness due to the similarity to cute characteristics in human babies [1, 2]. Their well-documented roly poly antics undoubtedly helps.

I admit that the giant panda is one of my favorite animals, but is not solely based on looks. This is a bear that lives in the dense green-gray hues of China’s mountainous regions and spends its days eating bamboo when its intestinal tract is designed to support a carnivorous diet [3]. They have a pseudo-thumb on their front paws that aids them in eating pounds of a plant strong enough for us humans to use it as scaffolding [4]. When their diet shifts from a mixture of bamboo shoots and leaves to mostly bamboo leaves, pandas shed their intestinal lining and reset their microbiome [5]! They are a true contender for winning “questionable adaptation” bingo.

One of Zoo Atlanta’s Giant Panda cubs showing the power panda skull structure as she enjoys some bamboo (photo credit Amanda Dunbar 2018)

In fact, giant pandas check so many ecologically weird boxes that I’ve found I get one of two reactions when this species is mentioned: fawning admiration or great frustration. There is never an indifferent reaction. Yet I never have to describe a giant panda. Iconic level status there – dare I say the Beyonce of bears.

So how does a bear acquire world-wide recognition with such conflicting reactions? Studies of the fossil record date the giant panda lineage (genus Ailuropoda) back ~7 – 8 million years [6], but giant pandas as we would recognize them, have existed since the mid to late Pleistocene ( 2.58 million to 11,700 years ago) [7]. At this point, giant pandas had adapted to a diet dominated by bamboo by evolving the skull structure for crushing bamboo [8] and their taste buds became more sensitive to tasting bitter flavors; this is a characteristic mainly seen in herbivores to help detect toxins (ex. cyanide or ricin) that naturally occur in plants to deter herbivory [9, 10].

One of Zoo Atlanta’s Giant Panda cubs assessing some bamboo before she takes a bite (photo credit Amanda Dunbar 2018)

This is the adaptation some people scoff at and use as an argument against giant panda conservation. From our perspective, it seems ridiculous for a bear to consume a fiber intensive diet with a carnivore’s digestive system – it shouldn’t exist! After all a giant panda can consume up to 40 kg of bamboo each day, of which only ~20% is digested to sustain itself [3]!

However, we are mistaken in thinking of bears as strict carnivores. Indeed, most bears are omnivorous and forage for fruits and seeds [3]. The giant panda’s dietary shift is thought to have occurred at a time when there was a decline in prey options but an increase in the abundance of bamboo forests [9]. Even with this “silly” adaptation, giant pandas are much older than us humans and have survived over millions of years consuming bamboo while other, seemingly, more ecologically fit species have failed [15].

With all of the attention to their dietary behavior, it is easy to lose focus on how giant pandas behave and interact with their natural environment. Giant pandas spend about 12 hours a day consuming bamboo with the remainder of their time being spent on foraging or sleeping [3]. Through their herbivorous diet, giant pandas spread bamboo seeds and open up patches for new bamboo forest growth [11, 12]. Without giant pandas, this unique forest and the biodiversity it supports would be in jeopardy [11, 13]. For this reason we should treat them like beavers which are esteemed ecosystem engineers. Instead, giant pandas are notorious for their diet-induced lethargy instead of receiving the credit their due as ecosystem engineers.

In fact we should give giant pandas more credit for their ecological role; giant panda habitat has the highest biodiversity when compared to ecosystems across the world, which means funding projects to protect habitat for giant pandas benefits thousands of plant, mammal and bird species. Healthy giant panda habitat also provides numerous ecosystem services, like clean water and carbon sequestration, to humans; a healthy giant panda population can also benefit local communities through tourism [13].

Yes, a great deal of money is spent on reproductive programs, which is another common target of people’s ire towards giant pandas [14]. Breeding programs often rely on artificial insemination due to the short time a female is fertile and receptive to a male; this method requires a great deal of time and resources yet does not guarantee a viable pregnancy. Other methods, like creating a DVD of “panda porn” to teach giant pandas how to mate, are treated as contemptible because researchers go to such lengths to encourage mating behavior [14, 18]. We have to keep in mind that a great deal of panda life history remains to be studied. Recent studies show that the vocal interactions between giant pandas and the competition for females are more important to successful mating than we previously recognized [18, 19].

Zoo Atlanta’s Yang Yang munches on bamboo. While mating attempts with his mate Lun Lun, keepers speculate that his gentle nature is not attractive to Lun Lun (photo and zoo keeper interview by Amanda Dunbar 2018).

However, we could also argue such efforts would not be necessary if habitat loss and fragmentation, due to increased farmland, and intense poaching did not take place. All of this occurred in the mere 53 years since the public first laid eye on Su Lin – the giant panda cub brought to the Brookfield Zoo in 1937. These intense pressures on the giant panda population ultimately led to their listing on the endangered species list in 1990 [15].

In 2016 the International Union for Conservation of Nature (IUCN) downgraded Giant Panda from “endangered” to “vulnerable.” While this is a reason to celebrate conservation efforts, the work is far from successful. Habitat degradation and fragmentation continue to be threats to bamboo forest habitat and are expected to be exacerbated by climate change [16, 17].

Call to action

You can help by donating to one of organizations that fund conservation projects for giant pandas and their habitat. Here are a few examples:
World Wildlife Foundation
Association of Zoos and Aquariums

[6] Hunt, R.M. (2004). A paleontologist’s perspective on the origin and relationships of the giant panda. In D. Lindburg and K Baragona, eds. Giant Pandas: Biology and Conservation. Berkely, CA: University of California Press.